BACKGROUND: Positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) is a useful technique for detection of malignancy. The purpose of this study was to determine if FDG-PET scanning using visual and quantitative analyses can identify patients with recurrent colorectal tumor following abdominoperineal resection. METHODS: Eighteen patients were evaluated for possible local recurrence of rectal carcinoma following abdominoperineal resection. The clinical presentation included rising carcinoembryonic antigen levels (n = 5), increasing size of a presacral mass on computed tomography or magnetic resonance (n = 13), or local symptoms (n = 3). Axial PET images of the pelvis were obtained following an injection of 10 mCi of FDG prior to biopsy. Quantitative analysis was performed by calculation of a standardized uptake ratio (SUR), and the images were interpreted by two radiologists in consensus. FDG-PET findings were correlated with histological or cytological findings and with the clinical outcome. RESULTS: Recurrent malignancy was confirmed in 13 patients by surgery (n = 8) or percutaneous biopsy (n = 5). Benign lesions were confirmed in five patients by surgery (n = 1), biopsy (n = 3), or clinical follow up (n = 1). Visual analysis of the FDG-PET data had a sensitivity of 92.3% (12/13) for recurrent disease (95% confidence limits; 63.9%, 99.8%) and a specificity of 80% (4/5; 95% confidence limits; 28.3%, 99.4%). SUR values were significantly higher in malignant lesions (range = 2.92-19.74, mean = 6.89) than in benign ones (range = 1.40-3.47, mean = 1.96; p = 0.002). CONCLUSION: FDG-PET is an accurate technique for detection of locally recurrent colorectal carcinoma. Visual analysis is equivalent to quantitative analysis for detection of disease.

Deoxyglucose↗

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Computed tomography of the ileocecal region.

The CT scans in 25 patients without ileocecal pathology and 52 patients with ileocecal abnormalities were retrospectively reviewed. The ileocecal region was identified in 18/25 (72%) of patients without pathology. Thirty of 52 patients with ileocecal pathology had inflammatory disease: Crohn's (13), appendicitis (9), abscess (6), and typhlitis (2). CT was complementary to barium studies, demonstrating wall thickening, pericolonic inflammatory change, masses, fascial thickening, and fistulae. Twenty patients had malignancy: primary carcinoma (9), metastases (7), and lymphoma (4). In all patients with carcinoma a mass was identified. Pericolonic stranding represented tumor extension in 5/6 patients. Metastases were identified as extrinsic ileocecal masses in all 7 patients. Liver, mesenteric and omental metastases were present in 8/20 patients. In patients with lymphoma there was wall thickening and two had additional pericecal lymphadenopathy. In 2 patients with hypoalbuminemia, findings included: wall thickening, mesenteric, and subcutaneous edema.

Abscess↗

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Computed tomography of prostatic and bladder rhabdomyosarcomas.

Rhabdomyosarcoma represents the most common soft tissue sarcoma in children. The CT findings in five patients with pelvic rhabdomyosarcoma are reported. In the three male patients the primary tumor originated in the prostate gland whereas in the two female patients the bladder was the primary site. The CT findings in the prostatic tumors included an enlarged, inhomogeneous prostatic mass with invasion of the perirectal fat. In two of these patients there was thickening of the levator ani muscle and one showed tumor invasion through the ischiorectal fossa and sciatic and obturator foramina into the pelvic musculature and bone. In the two patients with bladder tumors, one showed a large mass adjacent to the lateral aspect of the bladder and ascites, suggesting an ovarian primary tumor. The other patient with sarcoma botryoides (a subtype of rhabdomyosarcoma) had a diffusely thickened bladder. Two patients have had a follow-up CT demonstrating tumor regression posttherapy. The characteristically large size of these masses and propensity for local invasion in a young patient are typical features of pelvic rhabdomyosarcoma.

Adult↗

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CT demonstration of an adrenal pseudocyst.

The CT and ultrasound findings in a case of an adrenal pseudocyst are reported. The pathology, etiology, usual manifestations, and differential diagnosis of adrenal cysts are discussed.

Adrenal Gland Diseases↗

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CT appearance of diffuse mesenteric edema.

The extent of pathologic processes involving the mesentery is frequently difficult to assess by clinical examination and standard radiography. Contrast studies of the gastrointestinal tract only identify the effect of these processes on adjacent opacified bowel loops and frequently underestimate the extent of mesenteric pathology. Computed tomography has previously been used to characterize various mesenteric abnormalities, most often secondary to malignant or inflammatory disease. We report the characteristic CT appearance of diffuse mesenteric edema in 14 patients. Eleven patients had documented hypoalbuminemia, two patients superior mesenteric vein thrombosis, and one patient cirrhosis. The CT findings that allowed confident diagnosis of this entity include increase in density of the mesenteric fat, poor definition of segmental mesenteric vessels, relative sparing of the retroperitoneal fat, and association with subcutaneous edema.

Edema↗

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Computed tomography of masses in periportal/hepatoduodenal ligament.

The CT findings in 70 patients with masses in or adjacent to the porta hepatis/hepatoduodenal ligament were analyzed. Underlying disease processes included metastatic disease (44 cases), lymphoma/leukemia (10 cases), biliary carcinoma (seven cases), hepatoma (four cases), benign disease (three cases), and gallbladder carcinoma (two cases). Location of the mass was confirmed in 62 patients and showed six patterns: four along the hepatoduodenal ligament or within the porta hepatis; another within the liver impinging on the hepatoduodenal ligament/porta hepatis; the sixth, an intraductal mass. Of the masses along the hepatoduodenal ligament or within the porta hepatis the four patterns were well defined nodular masses caused by discrete nodes; matted masses due to confluent adenopathy; mixed, well defined and confluent masses in various locations along the hepatoduodenal ligament; infiltrating, enhancing soft tissue densities obscuring the portal vein margins. No disease specific pattern was seen; nonetheless, knowledge of these patterns is very helpful in detection of masses in this region.

Adult↗

PubMedDate not supplied

Hemiazygos continuation of a left inferior vena cava: CT appearance.

The CT appearance of hemiazygos continuation of a left-sided inferior vena cava is presented along with discussion of associated anomalies.

Azygos Vein↗

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CT appearance of focal pseudomembranous colitis.

Previous reports of the CT findings of pseudomembranous colitis (PMC) have demonstrated the diffuse form of the disease. Although the focal nature of PMC is well recognized in the gastrointestinal literature, this manifestation has not been stressed in CT reports. We present three cases of focal colonic thickening detected on CT that proved to be PMC.

Adult↗

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Computed tomography of primary retroperitoneal malignancies.

The CT examinations and medical records of 33 patients with primary retroperitoneal malignancies were reviewed. Computed tomography findings were then compared with those from scans performed on 122 patients with non-Hodgkin lymphoma who presented during the same time interval. Primary retroperitoneal neoplasms had three distinct CT appearances. Twenty-one patients (64%) had large soft tissue masses. Seven patients (21%) had masses with fatty density components, and five patients (15%) had tumors that were primarily of water attenuation. With the exception of those liposarcomas that contained recognizable fat, CT could not distinguish among the different cell types. Seventeen patients with non-Hodgkin lymphoma had large dominant retroperitoneal soft tissue masses that resembled primary retroperitoneal malignancies. In most cases, however, CT was able to differentiate these tumor masses from primary retroperitoneal tumors. Although 19 of 20 sarcomas of soft tissue attenuation were heterogeneous, only six of the 17 lymphomas presenting as dominant masses had such an appearance. Computed tomography is extremely helpful in initially evaluating patients with primary retroperitoneal tumors and in assisting the surgeon in planning his or her approach by accurately defining tumor extent.

Adolescent↗

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Computed tomography of renal lymphoma.

The CT studies of 29 patients with renal or perirenal lymphoma were retrospectively reviewed. Four patterns of disease were identified. Seventeen of 29 patients (59%) had bilateral renal masses. Only seven of these patients had associated enlarged retroperitoneal lymph nodes. Eight patients (28%) had single renal or perirenal lesions adjacent to or contiguous with bulky retroperitoneal lymphadenopathy. Three patients had infiltration of the perirenal space without significant renal parenchymal involvement, and one patient had a solitary renal mass. No patients in this series had diffuse involvement of the kidney without a focal mass. Renal involvement with lymphoma should be considered in any patient who develops multiple homogeneous solid renal or perirenal masses, even in the absence of other retroperitoneal disease.

Female↗

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CT of fundoplication.

To determine the CT findings postfundoplication, we retrospectively compared CT in 22 postfundoplication patients with CT in 22 patients with unrepaired hiatal hernias and gastroesophageal (GE) junction abnormalities and 24 patients with gastric or esophageal carcinoma involving the GE junction. Seventeen of the 22 postfundoplication patients had undergone a Nissen procedure. Of the 22 patients, 11 had esophageal dilatation, 14 had GE junction masses, 4 had esophageal wall thickening, 7 had surgical clips, and none had hepatic metastases or upper abdominal lymphadenopathy. Statistically, on CT, postfundoplication patients are more likely to have a GE junction mass (p = 0.023) and least likely to have wall thickening (p = 0.021). Nonetheless, because the findings occur frequently in each group, they are not diagnostic in the individual patient. However, 11 of 12 post-Nissen masses had the unique finding of an oval or linear central fat density within the mass. This finding was absent in the other postfundoplication masses and in those patients with repaired hiatal hernia or tumor. We conclude that pseudomasses occur on CT postfundoplication and can be indistinguishable from hiatal hernias and GE junction neoplasms unless a central fat density is present.

Adult↗

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Detection of focal hepatic masses: STIR MR vs. CT during arterial portography.

OBJECTIVE: Our goal was to compare short tau inversion recovery MRI (STIR) to CT during arterial portography (CTAP) in the detection of hepatic lesions. MATERIALS AND METHODS: Over a 24 month period, 40 patients evaluated for possible hepatic resection underwent T1, T2, and STIR MRI and CTAP. These studies were randomly ordered and interpreted by two independent readers. The total number of lesions and number of lesions within each hepatic segment were analyzed using McNemar's test. RESULTS: Readers 1 and 2 detected 95 and 91 lesions by CTAP and 78 and 83 by STIR, respectively, which was not significantly different (p = 0.1, reader 1; p = 0.4, reader 2). For both readers CTAP and STIR MRI detected more lesions than either T2 or T1 MRI (p < 0.01). In the medial segment, readers 1 and 2 detected 18 and 17 lesions by CTAP and 7 and 9 by STIR, respectively (p = 0.01, reader 1; p = 0.035, reader 2). CONCLUSION: Short tau inversion recovery MRI and CTAP are similar in total lesion detection except in the medial segment where lesions were more frequently identified by CTAP than STIR MRI.

Adult↗

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The diagnostic accuracy/efficacy of MRI in differentiating hepatic hemangiomas from metastatic colorectal/breast carcinoma: a multiple reader ROC analysis using a jackknife technique.

PURPOSE: Our purpose was to determine the diagnostic accuracy efficacy of a simple MR technique in differentiating hepatic hemangiomas from colorectal or breast metastases using a multiple reader method. METHOD: Thirty-seven cases with confirmed hepatic hemangiomas and 115 with confirmed hepatic metastases (colon primary, n = 86; breast primary, n = 29) evaluated with MRI at 1.5 T were retrospectively collected. A single lesion in a single slice from each patient was randomly selected; the images were masked and then were interpreted in random order by five separate readers blinded to the diagnosis using a five point diagnostic scale (from definite hemangioma to definite metastasis). Morphologic characteristics of lesion margin, signal intensity relative to other structures, and internal architecture (homogeneous versus heterogeneous) were also assessed independently of the five point diagnostic scale. Three of the readers had > 8 years of experience, while the other two had 1 and 3 years. The diagnostic scale results were subjected to receiver operating characteristic (ROC) analysis using a jackknife method. kappa-Statistics were applied to assess interreader agreement in the morphologic characteristics. A logistic regression model was used to determine which characteristics predicted pathology and reader diagnosis. RESULTS: ROC analysis showed the average area under the curve over all readers was (0.91 (0.89-0.93 95% confidence interval) (p < 0.0001). An analysis of variance showed no significant difference between the areas under the curves of each reader (p = 0.6433). When the definite and probable categories for hemangioma and metastasis were combined, the sensitivity/specificity for the diagnosis of hemangioma ranged from 57 to 73%/91 to 97%. The positive/negative predictive value ranged from 72 to 84%/87 to 91%. For the morphologic assessment, there was significant agreement between the readers (p < 0.0001-0.0037). A sharp margin and lesion signal equal to or greater than CSF predicted the presence of a hemangioma (p = 0.0148 and p < 0.0001, respectively). A sharp margin, lesion signal equal to or greater than CSF, and a homogeneous internal architecture all predicted the reader diagnosis of definitely or probably hemangioma. CONCLUSION: For multiple readers, T2-weighted SE MRI alone is a very specific method for distinguishing hemangiomas from metastatic colon or breast carcinoma. Morphologic characteristics of a sharp margin and a high signal predict the presence of a hemangioma. Last, reader experience does not appear to have a significant effect on the specificity.

Adult↗